text:
Why are there different starter limitations for dry cranking and manual start on the A320?
I recently had this point clarified that when we place the mode selector to CRANK on the A320 we can dry crank the engine up to 5 mins. But the moment we place the mode selector to IGN/START then we are limited to 2 mins (I'm mainly referring to the 2 mins with regard to a manual engine start) Could someone please explain why there are these two different limitations?

In CRANK mode, the air turbine starter (the thing that converts APU or bleed air into engine rotation) is working pretty hard, but nothing else in the engine is really doing very much. Speeds are slow, no fuel is being burnt, not much going on. After about 5 minutes, the starter will start to get hot, so you have to shut it down to let it cool off.
In START position, now there are lots of other things going on. Specifically, you are now introducing and burning fuel. That means a lot of things are going to get hot, besides just the starter. For example, you now have a bunch of hot gases going through the turbine. On a normal start, you will get to idle within 2 minutes or so.  But if you don't get to idle within 2 minutes, that means something is wrong.  There could be a bunch of different causes for this, but you don't want to continue to sit there and burn fuel while you figure this out.  If you do that, you could potentially overheat some other components (like the combustor or turbines). Depending on the cause, you might not overheat anything, but you don't want to risk it.
In summary, the 5 minute limit really just affects the starter. The 2 minute limit is for a bunch of other things (besides the starter).

if we leave the starter turning the engine during a manual start but we don't put the Master to ON then why are we limited to 2 mins. And during CRANK only 5 mins. After all in both cases the starter is only turning the engine and we haven't introduced any fuel as we haven't put the Master on. I'd imagine the starter will get pretty hot in 2 mins also.

Ok.  Maybe I misunderstood the question... if you are doing a manual start and have the master lever off, then you are correct that the situation is effectively the same as crank.  So I don't know why they would have that limitation. It is certainly not a limitation of the engine.


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Why can’t we perform CONFIG 1+F Takeoff in the following conditions as per the MEL?
I was reading in one of my company notices that we can’t perform  config 1+f takeoff on the Airbus A320 if we have the following faults.

SFCC SLAT CHANNEL FAULT
ADR 2 FAULT
IR 2 INOPERATIVE

Could someone explain the reasoning behind this?

@mins thanks a lot any idea about the other two faults?

Please, give details, which SFCC is faulty? It is allowed to have a faulty single SFCC, but not simultaneously a faulty ADIRU of the same order 1 to 1 or 2 to 2. If you are allowed to fly, all take off configurations are functional. Otherwise it is your own company decision , I can’t tell why.

@user40476 could you provide any official reference to your answer.

First of all SFCC1 regulates the engines idle, lo or hi, according to the Flaps/slats configuration, for instance to provide low idle at initial descent
Also SFCC1 uses the blue hydraulic circuit for Slats, in hydraulic emergency case, only blue might be available as being generated by the RAT
  therefore SFCC1 fault is a no go, SO I assume at takeoff SFCC1 is available
SFCC1 uses primary ADIRU1 so if ADIRU1 is also faulty we go into a no go condition
Now if ADIRU2 is faulty, SFCC1 should rely on a single airspeed data, therefore if the speed is incorrect premature automatic retraction of the flaps might occur at takeoff, that is going from 1+F to 1 automatically, so take off with configuration 1+F is prohibited with these faults at takeoff

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text:
Why is the A320 pre pressurised before take-off?
I know this question has been asked, but I still haven't understood the answer. In the A320 the cabin gets pre pressurised before takeoff as we apply takeoff thrust. What I don't understand is what is the exact reason behind this. A little technical answer will be much appreciated.

Related: Why is cabin pressure increased above ambient pressure on the ground?. The part you may have not understood could be "This ground pressurization of the cabin makes the transition to pressurized flight more gradual for the passengers and crew, and also gives the system better response to ground effect pressure changes during takeoff." (236 ft below the runway)

@mins That answer has a lot of technical detail to get through along the way to that basic, conceptual answer.

@Ralph J can you please explain what is this pressure bump I have come across this term before but no one could exactly answer what it is?

@Jai It is a relatively small but very abrupt change in the cabin pressure. Closest analogy outside of pressurized environments would be a fast elevator that makes your ears pop. Noticeable, perhaps startling, and generally undesirable in the airlines world where passenger comfort is important.

I'm confused.  Given that most airports are below 6-8K ft, wouldn't pressurizing the cabin on the ground actually mean depressurizing it somewhat?

@jamesqf Differential pressure versus absolute pressure, much like AGL versus MSL. The cabin is pressurized to -236 feet current AGL. Lower altitude == higher air pressure.

In general, you want the cabin to be

pressurized in flight, and
not pressurized on the ground

If the system followed only & exactly that logic, at the moment of liftoff it would start pressurizing immediately, with the goal of overcoming the sudden change in pressure due to the aircraft's rapid climb away from the ground, but not more than that so that you don't pressurize below ground level all at once.  In practice, that ends up being a pressure "bump" right at (or slightly after) rotation, which is undesirable since it is at least noticeable and potentially uncomfortable or startling.
To prevent that pressure bump, the pressure controller is programmed to slowly pressurize the cabin slightly while the aircraft is still on the ground, so that at liftoff it is essentially maintaining the differential it has, rather than starting pressurization all at once.

It's also an opportunity to check that the pressure can actually increase and there are no leaks.

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text:
What is the background of the maximum altitude formula?
This question What determines the maximum altitude a plane can reach? has a formula at Peter Kämpf's answer :
$$\rho_{min} = \frac{2\cdot m\cdot g}{(Mach^2 \cdot c_L)_{max}\cdot a^2\cdot S}$$
Does anybody know what's the name of the formula or who has developed it?
Could anyone explain why $Mach^2 \cdot c_L = 0.4$ is a good value? What determines good or bad values for airfoils or what type of airfoils is requested?

The formula can be derived equaling the weight ($W$) of an airplane with the maximum lift ($L$) generated by its wings. I'm not aware of any special name for it.
$$ W = L \\
m\cdot g= \frac{\rho_{min}}{2}\cdot V^2\cdot S\cdot c_{L,max}$$
Substituting the aircraft's speed with an expression containing the Mach number ($a$ is the local speed of sound),
$$V=Mach \cdot a$$
and solving for the density you get the formula in Peter's answer:
$$\rho_{min} = \frac{2\cdot m\cdot g}{(Mach^2 \cdot c_L)_{max}\cdot a^2\cdot S}$$
At high speeds the maximum lift coefficient is not constant. That's the reason why the Mach number and the maximum lift coefficient are written together in one term: $(Mach^2\cdot c_L)_{max}$. In order to fly as high as possible this term has to be maximized.
With supercritical airfoils you generate less drag and can therefore fly at higher Mach numbers, increasing this term.
I don't think the value 0.4 is a physical limit. Probably it is just an empirical value which takes many real-world constraints into account (if there is a physical limitation I'd be glad to read an answer explaining it). If you calculate $(Mach^2\cdot c_L)_{max}$ using U-2's data you get indeed a value close to it.

I learned the formula from Mark Drela, and I also don't know a special name for it. It is easily derived, as you showed. The 0.4 is indeed empirical and what I found to be common to good designs. Maybe you get a little above that with supercritical airfoils, but not with "regular" airfoils which stay below their critical Mach number.


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How to best recover from an excessive descent?
Suppose I found myself in a rapid, steep descent, perhaps right after breaking a spin. E.g. a 60 degree nose down with 100kt and accelerating rapidly, on a Cessna 172.
What might be an ideal recovery strategy, other than trying to guess/feel the optimal back pressure on the yoke? Obviously, if I pull back too hard I risk overloading the wings (to the point of collapse?) whereas if I pull back too gently I risk gaining too much speed, losing too much altitude, etc. Among other considerations, would it be advisable to enter a slip to (greatly?) increase the drag?

In what conditions? A 172 is typically very easy to fly, and is self-righting so the conditions in order for the rate of climb/descent to extend past the typical envelope must be abnormal or intentional. What is the initial alt. of descent? In order for you to get a detailed answer you need a sufficiently detailed question.

Sideslips at high G and/or high speed aren't a good idea structurally.
Absent a G meter, airspeed and judging G load is all you've got.  If I found myself going straight down at 100 kt, I would try to keep the speed below maneuvering speed, 128 kt, but if I felt I was applying too much force and risked an accelerated stall, I would let it go faster and if the air was smooth I'd let it go up to Vne if necessary.
And in a really extreme case, if the choice was exceeding Vne or maybe pulling the wings off, I'd take my chances exceeding Vne.  If you have to exceed a parameter, it's safer to go too fast than to pull too hard, because there is ample safety margin for flutter, and you know how much you are going over.
Of course, without a meter, with G load it's all judgement.  The yield G limit for normal category is 3.8, so what can be really useful is go with your instructor and practice 60 degree banked level turns to become familiar with the sensation of 2Gs, which will at least give you a reference point.  Even better if you can get a ride in an aerobatic airplane and learn what 4 Gs feels like and try to stay below that when the time comes.
The other big thing is knowing whether you are in a dive inverted or right side up.  This is a problem for pilots who get flipped over by wake turbulence and end of upside down in a 45 degree dive, and instinctively pull right around in a split S through 90 degrees and rip the wings off.  In an inverted dive most airplanes will accelerate past Vne in a heartbeat.
If you are in an inverted dive like that you have to roll the plane right side up before pulling out.  Recognizing it takes training and professional pilots often get upset training in aerobatic aircraft to develop the correct reactions.

First and foremost determine your attitude after you break the spin (or any other unusual attitude for that matter).  You first stop with your eyes should be the airspeed indicator.  If it’s rapidly increasing, you’re in a dive and your next step should be to get the throttle to idle - PRONTO.  If your airspeed is rapidly decreasing, you’re in a climb and you need to increase the throttle to full power to delay the onset of a stall.
If you’re in a climb - relieve aft elevator pressure or push forward on the yoke until the nose of the aircraft returns to the horizon.  Once you’re in a level pitch attitude, roll wings level with aileron input.  Then set power and trim for straight and level flight.
If you’re in a dive - This one is far riskier as you’re both rapidly accelerating towards Vno and Vne, not to mention about to have an appointment with terra firma if you don’t do something quick about your situation.  As such your corrections here need to be prompt but not excessive such that you induce a secondary stall or overloading the airframe, causing structural damage or failure.  Your first step here will be to ROLL WINGS LEVEL.  Attempting to recover here by first applying aft elevator pressure before rolling wings level may place the aircraft into an even tighter spiral with your inputs pushing the airfram to its structural load limits. Attempting to apply elevator pressure combined with aileron inputs at speeds at or beyond Va can potentially overload the airframe as well, resulting in structural damage, so your second step if you’re in a dive after reducing your throttle to idle MUST BE TO ROLL YOUR WINGS LEVEL.  If you cannot ascertain your attitude by looking outside of the aircraft, look at your attitude and roll the airplane level accordingly.  Once you have wings level, apply aft elevator pressure, being careful not to over stress the airfram nor so aggressive that you exceed the critical angle of attack induce a secondary stall.  Once level, set power and trim for straight and level flight.
So to sum up:
In a climb - indicated by rapidly DECREASING AIRSPEED:
Throttle - Wide Open
Alleviate aft elevator pressure / push forward on the yoke until nose level with horizon.
Roll wings level
Set power and trim for straight and level flight.
In a dive - indicated by rapidly INCREASING AIRSPEED:
Throttle - Closed
ROLL WINGS LEVEL
Apply aft elevator pressure until nose level with horizon
Set power and trim for straight and level flight.

PARE (power to idle, ailerons neutral, rudder to break
spin, elevator to recover) works really well in the 172.  Firstly, if you did your CG homework before you
went flying and did some stalls with your instructor you would know the 172 has a very gentle, straight forward stall. No need to slam the yoke full forward
to recover.  If you do over do it, no time for sight seeing, immediately pull out of the dive. The key is not to wait even a second, as speed will quickly build.
The 172 is very stable, so once you break your spin
(which you have to try very hard to get into),
easy down el while checking your airspeed, and then
fly out of it adding throttle as needed.
I would very much recommend going over this with a qualified instructor and make sure you have adequate
altitude before even thinking about trying it.
Bob

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text:
What is the difference between static and dynamic seals?
What is the difference between static and dynamic seals and  How much leakage is allowed past each seal?

Generically speaking:

A static seal is a seal between two surfaces that don't move relative
to each other.
A dynamic seal is a seal between two surfaces that do move relative to
each other.

The amount of allowed leakage depends on the application.


text:
How is fuel planning done for a VFR flight that involves multiple full stops?
Doing first cross country flight plan with several stops along the way.  What is the general rule of thumb for calculating time, fuel, etc. for a mid trip landing?  I've done conceptual flight plans with checkpoints etc, but not actual stops.
In other words, I can calculate fuel burn, ground speed, course etc. for a point to point flight.  Just not sure what to calculate in by adding a full stop in the middle of that same flight.
While studying for the FAA knowledge exam it sometimes said calculate 3 minutes for take off and departure but curious if there is a generally accepted set of numbers.

Welcome to Av.SE!  I'm not clear why you need to plan through the stop; why not simply treat each leg as its own flight?  If you need to figure an ETA to the last landing of the day, just allow yourself more time than you'll need at each airport, and know that your final ETA will mostly depend on your actual takeoff time from your last departure airport. Or are you trying to fuel-plan for taxiing back from a full stop? Ask your CFI what burn to use in that case for your aircraft.

For your purposes, what's the difference between one flight with a stop in the middle, and two separate flights? What exactly do you mean by a "full stop"?

Great point about treating like two flights.  My main interest is properly calculating total fuel burn.

This may not be what your CFI is looking for, but I found the changes in fuel consumption during takeoff/landing to be negligible. This is because the taxiing uses very little, the and extra fuel burn in the climb is largely compensated by the savings in the descent. So, I just look at the distance between the airports, take winds aloft, calculate ETE and make sure it's acceptable in respect to fuel reserves. Ditto for any foreseen diversions. You have to have enough fuel on board to reach your planned reserve airport if you arrive at your destination and find that it's closed (e.g. because of an accident). This may be less of a problem in North Carolina, but in New Mexico, you might need to return all the way. A 30 minute VFR reserve isn't going to cut it.

I usually use a gallon (Piper Cherokee 180) for taxi, and my normal climb out and descents.  Assuming you’re calculating Top of Descent for the middle stop, and top of climb when leaving, I’d just through those burns in there, plus, maybe, 3x your taxi requirements for parking, shutdown, startup, and taxi back.


text:
How does 700 AGL class E protect IFR traffic?
Sometimes class E airspace goes down to 700 AGL to protect IFR traffic departing/approaching an airport. But I'm failing to understand how this works in practice. Let's look at one example: N51 Solberg airport.

There's class E going down to 700 AGL surrounding N51. And N51 has a RNAV (GPS) RWY 4 IAP  that has MDA of 511 AGL.
Suppose the cloud is at 699 AGL, and some person is flying VFR at 698 AGL (it's class G so they just need to stay clear of clouds), and I'm flying the RNAV RWY 4 approach. As I break out of the clouds with a 500 ft/min descend rate I could immediately collide with that VFR traffic.
So how does this class E airspace offer any safety guarantee to IFR traffic?

Many other examples exist - e.g. CVO.  The short answer to your question (too short to post as an actual answer) is -- "it doesn't."

It is not about VFR.
Airspace is about ATC, and ATC is about separating IFR traffic from IFR traffic, and IFR traffic from terrain. Class E doesn't mean radar coverage, it only determines who has this IFR separation responsibility.
What 700ft provides is the ability to vector and set air routes at 1000ft agl, and thus the initial fix for an approach. It also allows much better traffic flow because ATC can't stack class E instrument approaches, it is considered a black box and they can only clear one airplane for the approach at a time.
A 300ft buffer is required from the bottom of the airspace when designing routes or vectoring traffic, 700 becomes 1000agl. (Including a surrounding obstacle-free buffer area and rounded up to an MSL divisible by 100.)
So the short version is that it provides a known obstacle-free area to a lower altitude. Which can also affect the safety of missed approaches and holding.

Not sure I follow exactly. ATC cannot vector aircraft below the MVA/MIA (with some exceptions) and that altitude will be at least 1000' higher than any terrain or obstructions in the vicinity, that is, it is very very unlikely for the MVA to be any lower than 1300-1500 AGL or so. You are right that ATC doesn't vector in Class G as a general rule, but the E dropping from 1200 AGL down to 700 AGL doesn't help us at all really.

@MaxPower - surely the FAA has some guidance on how to adequately   protect IFR traffic (e.g. just emerging from clouds) from VFR traffic?  I have a hard time believing that these 700' class E floors were not intended to help with this- in some way-- yet at the same time it seems that they are sometimes spectacularly far from adequate--

Minimum VFR cloud clearance in class E is 152, if it remained class G it would be clear of clouds, so it changes that much. It has been a few years since I was tuned up on the specifics of terminal procedures and airspace design so I will need to come back after refreshing myself. But there are a lot of cases where they just rely on the "big sky" method rather than positive separation. eg in northern Canada an IFR flight is not given ATC separation,(basically IFR in class G) traffic per volume of airspace is so low that the odds of air to air collision are considered insignificant.

@randomhead The floor of the airspace must be at least 300 feet below the MVA, if the MVA is 1000agl then the airspace must be 700 or lower.


text:
How to calculate lift and drag coeffecients for VTOL aircraft in the takeoff stage?
How would I calculate CL and CD for a VTOL aircraft while it is in it's takeoff/landing stage?
The particular aircraft is a fixed wing/quadcopter hybrid so I know that I can treat this as a thin rectangular plate problem. However, because the aircraft takes off vertically, I do not understand what formulas to use to calculate these coefficients.
If I use CL=2$\pi$$\alpha$, where $\alpha$=$\pi$/2, then I end up with CL=9.87, which just doesn't make sense.

At $\alpha$=$\pi$/2 the flat plate is perpendicular to the air stream.
CL is defined as the force perpendicular to airstream, CD as the force in direction of the air stream. When the craft takes off vertically, its CD is high and its CL is zero.
A graph and a most excellent explanation here

Nitpick: Lift is a force, $C_L$ is an non-dimensional coefficient.

"Lift" (vertical takeoff) would be the aircraft weight + drag at the desired rate of ascent.  The aircraft will accelerate upwards until thrust (vertically) = weight + drag.
Drag coefficient can be modelled from flat plate or other appropriate flat shape
(top view of the aircraft would be best), but keep in mind the ascent rate will be relatively
slow and the majority of engine power will be used to overcome weight.
The power required curve, with an adequate safety margin for downdraft, would be
at maximum for liftoff and ascent, reducing as aircraft begins to move forward and the wing begins to generate lift. This power/thrust reduction could be from over the weight of the aircraft at lift off to less than 25% of it in level flight.
Interestingly, all aircraft do this transitioning from climb to level flight as they reduce power and "level off", again using the more efficient wing for lift instead of their prop.  VTOL aircraft simply do not use their wings at all for lift off.
Power/thrust requirements considered, a STOL may be a happy compromise.

Since you listed it as a quadcopter with a fixed wing, I'm going to assume (at least in the takeoff/landing stage) that the propulsors are perpendicular to your wing. The simple answer is, your total thrust is equal to weight; consider your lift to be close to zero and your lift coefficient is undefined.
Angle of attack only really makes sense when the forward relative airflow (that is, incoming flow more or less parallel to your wing) is greater than the vertical relative airflow. For reference, a one-to-one relative airflow is 45 deg AOA.
Furthermore, the lift slope of $2\pi$ is for an ideal thin airfoil section (2D); for a 3D wing, it will be less due to induced drag. Even for a section, it is only true for small AOAs (certainly less than 15deg). Above that, the lift slope is no longer constant. Close to 90deg AOA, the concept of airfoil no longer applies and you'd be looking at blunt-body aerodynamics.


text:
What are the restrictions preventing more intelligent autopilot systems?
Current autopilot system is integrated with Flight Management System (FMS) for navigation such as LNAV and VNAV; both of them are based on preset parameters given by the pilot prior to departure (IRS alignment, total fuel/pax, waypoints/airways, flight level, etc) or in short, expert system
What are the restrictions for intelligent system autopilot in which the autopilot shall assist the pilot for making decision (or the autopilot decides per se)? For example, during flight under certain condition where some sensors are failed and flight control system reverts back to direct law (in case of FBW) and the intelligent system autopilot recognizes this case so it helps pilot to decide what to do or controls the aircraft thoroughly

If the computers were able to control the aircraft, then why would reverting to direct law (I think that's a strictly Airbus term, by the way, and not general to FBW systems) be necessary? The point of reverting to direct law is that the computers aren't able to safely control the aircraft in its current condition.

@MichaelKjörling my mistake, sorry... yes, direct law refers to Airbus term for direct control from pilot to the flight controls; perhaps I was mixed up
what I meant is should that case happened the autopilot does not disengage but rather keeps the aircraft in its current flight although it lost several sensors in order to fly normally (and other cases as well). Thanks

You might be interested in Does engine failure shut off the auto-pilot? which, while not a duplicate, does discuss different autopilot modes on commercial aircraft and how the autopilot(s) can interact with various failures.

What do you mean by "what are the restrictions"? Are you asking what legal restrictions there are on doing this?

@TannerSwett ... yes that's exactly what I mean, more to philosophical/regulatory aspect instead of technical

@MichaelKjörling thank you very much for your link that helps me finding hints on the subject

I like this question a lot, but it's hard to answer a vague "why not" question.  There are many decisions still left to the pilot (see this question or this one), are you talking just about sensor failure or are you also talking about other scenarios like engine failure, responding to weather, route planning, etc?  What scenarios do you wish the autopilot handled?

@CodyP sensors failure is just one example case where the A/P fails accordingly but this may lead to another problems pertaining the A/P system such as those you mentioned ... from what I understand about intelligent system is that it has the ability to "learn from previous the similar cases" thus the A/P system could overcome the problems and fly the aircraft safely; although technically speaking it "might" be possible, the FAA/CAA regulation might strictly restricts the use of intelligent system for the sake of safety (intelligent system itself in aviation might be considered as "hazard")

@CodyP as an addition ... the scenario might be anything but I was thinking of such case like Birgen Air 301 or Air Asia 8501. Thanks

Under the FAA there are not really regulations that limit the ability of an autopilot and shy of takeoff most modern systems are capable of performing most of a full flight with no pilot input (aside from route updates etc). Ultimately any aircraft system will have to get certified and this involves rigorous testing as well as demonstrations the system works under all stated cases.
There is however a bit of a logic issue in your statement:

For example, during flight under certain condition where some sensors
  are failed and flight control system reverts back to direct law (in
  case of FBW) and the intelligent system autopilot recognizes this case
  so it helps pilot to decide what to do or controls the aircraft
  thoroughly

The reason the autopilot disengages or disconnects is because, due to the sensor failure, it no longer has the information it needs to properly control the aircraft. No matter how smart the system is, without proper sensor input, positive control is not possible or would be logically unsound. This is even true for human pilots and was in part the issue that lead to the Air France 447 disaster.
There is a broader question here of autopilots potentially handling emergencies which is a bit different than a sensor failure (read pitot static failure). This is already in place in part on some aircraft and as time moves we see more and more of it. Aircraft are now capable of detecting a depressurization and automatically descending to a safe altitude; even new small GA planes have this feature. Autopilots also now have forms of automatic level mode which will bring the aircraft back to a straight and level attitude at the push of a button.
This also comes down in part to design philosophy. This is highly opinionated so I'll stay away from it on this site, but there is hard data to support both cases: in the event of an emergency, is a pilot or computer system better equipped to handle the situation?

One could make the case that, with a sufficiently robust ap, that if the ap doesn't have the necessary information to safely fly the plane then neither do the pilots

@TomMcW yes I agree with you, should anything fails then the control reverts back to the pilot and at this present time (at least for now) we cannot rely on automated system entirely

I'm not an expert, especially on the regulatory framework, but I can make a limited answer.
In some ways aircraft already are making incremental steps towards more automation and fail-proofing:

Airbus, among others, has integrated TCAS into autopilot to automatically fly conflict avoidance maneuvers
Systems like the F-16 Auto-GCAS allow the plane to refuse to crash into the ground, and has already saved several lives in the military.
Some planes have an emergency descent system that will automatically descend if the cabin depressurizes
Navigation technology is evolving to the point where many aircraft currently manufactured don't even have VOR, and you can now make approaches down to 200 ft using only GPS, and follow curved paths with guaranteed high precision.
FADEC's, which came into service in the early 80's, take complete control of the engines from the pilot
Boeing is looking at a variety of ways to further automate the cockpit and reduce pilot workload (example source)

Airplanes already try to revert to basic functionality when something fails.  Localizer beacon failure doesn't disengage the whole autopilot, and many autothrottles can work with one engine out.  There may be some room for improvement in specific areas though - but bear in mind many of these sets of redundant sensors are already designed to have less than one complete failure per million flight hours.
Some of the problems don't lend themselves to an easy solution- if you're engaged in altitude hold and you lose your air data sensors, how do you measure altitude to maintain altitude? You could create a new sub-mode for level flight based only on the IRS, but this would be a lot of complexity compared to the alternative of hand-flying or just going to a basic pitch hold mode.
Sure, you could get around these dangerous scenarios by taking more authority in and reverting better to basic systems or modes when something fails, for example going into speed on pitch when both engines fail.  Or in the case of Indonesia flight 8501 that you mentioned, forcing a backup flight computer to always be on during flight and somehow refusing to allow a dangerous roll to occur at the moment the autopilot disengages.  However, in all these situations, you're trying outsmart the pilots and take decisions from them, which is... complex.
Some manufacturers give the pilot full authority, some limit the pilot only to what's known to be safe. While in my experience avionics engineers are happy to overthink things and try to idiot-proof their systems, these kinds of new systems come with a lot of difficulty in human factors testing, increased complexity, etc. and so changes are only made incrementally.
There is some regulatory work I'm aware of behind this.  For example, planes are designed to be predictable and deterministic: the thought of untested scenarios or non-deterministic code keeps certification authorities up late at night.  This limits development to maintainable, modular segments of flight and behavior.  It's also easier to certify and train for incremental changes than a complete redesign, especially given how incredibly complex modern avionics are.

Thank you very much for your answer, so based on the description you wrote and by the FAA/CAA regulations it is possible to implement but we must also consider which field does the IS will take part especially on essential system like flight controls; this includes flight dynamics, electro/hydraulic/pneumatic actuators, sensors; outsmart the pilot by intelligent system is (IMHO) nearly impossible due to the fact that pilot must be the last line of defense should anything fails, perhaps the IS takes part as an advisory instead (if it is designed not to handle abnormal maneuver)?


text:
Wing flex physics?
What physics is involved with wing flex when in air?
A simplified answer will suffice.
I can understand when on the ground that a heavier wing makes it bend more down.
My feeble understanding:
When in air isn't it only positive G that makes it bend up, and weight of wing don't really matter, instead the weight of the body matters, yes? If that is the case the amount of normal force don't really matter, correct?

"the amount of normal force don't really matter..."  Which normal force might you be referring to in this sentence?

Normal force. Its equal to lift at AoA of 0. At AoA of 90 its equal to drag.

Yes, weight distributed well outboard on the wingspan decreases the wing-bending moment in actual flight, unlike the case when the aircraft is parked on the ground.

Some info in this post

Here's a simplified, almost trivial answer.
Call "normal force" the component of the net force on the wing that is perpendicular to the wing chord.  The net force: gravity (in whatever direction), plus any force due to air moving past it (in whatever direction(s)), plus any force due to mounted ordnance, or mounted thrust-vectored engines, or air-show wing walkers, or giant magnets, or whatever.
The greater that force, the more the wing bends.
The stiffer the wing (spar), the less the wing bends.
The more that force is nearer the tip than the root, the more the wing bends.
The wing just acts like a (complicated) spring, roughly obeying Hooke's law.

It is important to mention that gravity means just gravity acting on the wing itself. If you add the weight of the fuselage, you'll obviously get zero for level flight, but the point is to get the force between the two.

Yes.  "Net force on the wing," not on anything else.

Although I wrote a simplified answer will suffice, I maybe didn't mean that simple. But its okay, I found a good answer elsewhere. I will mark this as answer at least until somebody answers with a little more details, perhaps some formulas.

@Invariant, if you found a good answer elsewhere, would you mind giving a write-up here and posting it? Answers to own questions are always appreciated.


text:
Surface deflection if loss of hydraulics on combat jet
In a typical combat jet from the 1970ties, at loss of hydraulic pressure, how does the deflection surfaces behave?
If it happens on the runway, will the weight of the surfaces make them deflect downwards?
If it happens at speed, will they align with the incoming airstream?
I heard something about a Hydraulic lock, is such a thing common in fighter aircraft and will it make the surfaces 'freeze' at hydraulic loss?

Depends on the type of actuator; idling or non-idling.  If idling, there is an internal idle circuit that ports the extend and retract side of the actuator cylinder together when there is no pressure.  Such an actuator can be moved when something drives the surface  while the actuator is unpressurized, and the fluid within will just circulate between the extend and retract sides. There is usually some restriction to this idle flow so the unpressurized actuator still provides flutter damping.  You know an actuator has an idle circuit if the surface starts to sag part way over time when the aircraft is sitting unpressurized on the ground.
If the actuator has no idle circuit, and there is no extend or retract input to the servo control from the control system, it will be hydraulically locked at that position because the fluid on the extend and retract sides has nowhere to go (assuming the fluid isn't gone obviously).  To move the surface of a no-idle actuator while unpressurized, you have to displace the servo control by moving the controls, which will connect the extend/retract chambers to the pressure/return sides of the hydraulic system to break the hydraulic lock and allow the actuator to be moved.
If there is a dual actuator installation with no-idle actuators and one of them is unpressurized, it will be hydraulically locked while there is no control input, but when you move the stick, the gang bar linkage interconnection of the two servo valves, that synchronizes them, will break the lock to make sure the unpressurized actuator doesn't resist the pressurized one.
With a dual actuator installation with idling actuators, when one is unpressurized it just becomes a flutter damper, and if both are unpressurized, the surface will sag on the ground or, if it was an aileron say, it would float up in flight.
A non-idle actuator would only sag on the ground or float up in flight if the control circuit itself is displaced to break the hydraulic lock that is set up whenever there is no servo input.
So if you have say a single no-idle actuator on an aileron while flying, and the pressure is lost, it will sit there at neutral, hydraulically locked there.  If you were to move the control stick to displace the servo input, the hydraulic lock would be broken and the surface would float up.  Normally they are in pairs so you'd have to lose both hydraulic systems for this to happen.
So, if the airplane you are concerned with has controls that sag when the airplane is parked, it has idle circuit actuators that would allow the surface to float or otherwise align with the stream, or sag if on the ground, if the surface was completely unpressurized.  If the controls stay rigidly at neutral and can't be moved when the airplane is parked unpressurized (unless someone moved the stick while you push), it has no-idle actuators and they will stay at neutral in flight unless you move the stick.

All flying control surface actuators act as dampers when unpowered, for redundancy sake. It would not be good having 2 actuators powering the surface, where one would lock it if unpressurised.

Not true.  You didn't read carefully.  When you have two non-idling actuators together, they are both operated by a common gang bar.  If one is unpressurized, the gang bar displaces the servo valve of the dead actuator at the same time as the live one, so that the hydraulic lock in the dead one is broken during the movement.  If you go to the ailerons of a lot of jets with dual non-idling actuators, they are locked solid while unpressurized.  You can move the surface if someone in the cockpit moves the controls from neutral to temporarily release the hydraulic lock.

One actuator powered by hydraulic system 1. The other actuator powered by hydraulic system 2. Each totally independent of the other for redundancy sake. You did not explain carefully, pictures and references help.

They are controlled by a common gang bar coming from the aileron cable circuit. When one servo valve is operated, the sister one gets an identical input.  The poster wasn't asking for a detailed description of how these things work, just what happens if this or that.

Yes, the input to both actuators can come from one source. That also means that a cable jam renders the aircraft incontrollable, so for instance on the 737 there are 2 cable circuits in aileron and elevator which can be decoupled.

That's why they split them left and right side on pretty much all transport category airplanes.

Most of the ones that we measured without hydraulic pressure would just sit there. Moving the stick is possible within the servo valve deadband, but the surface does not move whatsoever, just stays in the last known position.
Hydraulically powered fighter jet surfaces are powered fully redundantly, by separate actuators and separate hydraulic systems. If pressure fails in system 1, opening the servo valve (by moving the stick) just connects pressure to return and its actuator becomes a passive damper that otherwise does not hinder the functionality of the remaining one. Yes the inputs to both servo valves are linked.
Most hydraulic power systems for fighter jets are irreversible, meaning the aerodynamic hinge moment cannot move the stick. But if the hinge moment becomes larger than the total force of the active actuators, the surface cannot be deflected anymore.
Info on military jets don't seem to be not publicly available. I could find this hydraulic schematic for a G450 elevator:

This set-up allows manual reversion: when all hydraulics are off the pilot can manually deflect the elevator, at higher forces than with hydraulics functioning. Note that the pink colour denotes "Hydraulic Lock". It means that when the servo valve is closed, back driving the actuator is not possible due to trying to compress the hydraulic fluid.
Over (a very long) time, gravity may slowly push the hydraulic fluid back through the circuit when unpowered. When all oil in the circuit has seeped back into the reservoir.


text:
What is the difference between auto-start and manual start in an A320?
What is the difference between auto-start option and manual start in the Airbus A320?
Can you please explain

In Auto-Start option you just press the button, and wait until the engine starts. In manual option you need to monitor all parameters, you need to open valves manually, ignition manually etc and etc. You can check video for 100% understanding:


text:
Is it standard procedure to unlatch the cockpit door before an emergency landing in a small aircraft?
I was watching an Air Safety Institute video called "Real Pilot Story: Cemetery Crash – A near-death experience with valuable lessons for all pilots." It discusses a situation where a 1958 Bonanza crash landed in cemetery due to an engine failure.
At the 2:23 minute mark they are discussing the lessons learned and the pilot states that "I should’ve reached across and unlatched the entry door because that could jam in a landing, and in a Bonanza it’s very difficult to get out if you jam that door."
Is that really the proper procedure in the case of a crash landing? It seems a little strange to suggest that, while trying to land safely, the pilot should pop the cockpit door open.

Yeah, getting trapped in a burning plane with the door crushed and locked in place would be bad.

As always check your POH for procedures, however most light aircraft call for unlatching the door in the event of an emergency landing or ditching.  Two principle reasons: 1. It aids egress, which can be difficult with a jammed door. 2. It allows better energy absorption of the front part of the fuselage, by permitting it to crumple better.

In the 60s with some aircraft (PA28?), it was suggested that not only do you unlatch the door, but to use an object such as a shoe or rolled up jacket to keep the door slightly ajar in preparation for a forced landing. (although I remember that this was something that you'd get your passenger to do, if you had one) This aircraft had only the one door for exit; kicking out windows was never a practical alternative.
Apart from frontal impact damaging the door, if the aircraft should end up upside down, the top of the door of some low wing aircraft curves over to become part of the roof contour & thus could make getting it open (from inside or outside) particularly difficult.
Also, as with everything else in flying, there's a check list. If prepping the door is on the list, you do it, only takes a moment.


text:
How many landings per year are performed using the integrated standby instrument system?
Could you tell me how many landings are exclusively driven by Integrated Standby Instrument System or equivalent in the world per year ?
Same question with "partially" using instead of "exclusively".

Hello Yan, welcome to aviation.stackexchange! I have made a few changes to the title and the text, I hope it is in line with what you intended it to be.

Yes thank you DL. It surely is better written and still is in line :-)

None, as far as I have ever heard of. There may be an instance out there of failure of both/all of the INS’s or displays, but in the airline world at least, it would have to be absurdly uncommon.
It is nice to have the standby ADI as a tie-breaker between the two primary displays in case they should happen to disagree (which was more likely with mechanical instruments than with electronic displays), but actually losing everything else & using just the standby to landing - between really rare and unheard of.

Thank you Ralph.
Seems to answer quite pretty well to the "exclusively" question...
Maybe someone has more precise information about the "partially" question :-) ?

If you have at least 1 primary flight display, you aren’t really “partially” using the standby indicator for anything. If it’s all you have, then you’d be using it fully, but if you have something else, then THAT is what you’re fully focused on. I can’t come up with any scenario for partially using the standby ADI.


text:
Does a conversion for wheel to floats require an STC or Form 337?
When you add floats to a tricycle gear (e.g. Beaver) do you need an STC to install the TSO'd floats? Or can this installation be approved with a Form 337 for a single aircraft?

I don't have all the references so this is not a complete answer. An STC is a modification that has been "pre-approved" by the FAA Administrator for a specific make, model, and sometimes serial number of aircraft. An STC meets - "minimum standards for the design, material, construction, quality of work, and performance". A Form 337 is an application for a modification that is not "approved" so the applicant must show it is airworthy and meets the necessary requirements for being added to an aircraft. https://www.faa.gov/documentLibrary/media/Advisory_Circular/AC_21-40A.pdf

It is possible that a logbook entry is all that is required.

@acpilot I suppose you might be right, but switching to floats certainly seems to be a major alteration. Or perhaps you are considering an aircraft that is already certified for floats?

Yes, already certified.

I am assuming the airplane is not already certified for floats. Therefore I don't mean a plane that is already certified for both land and sea ratings with the option to switch back and forth between wheels and floats. Instead I am referring to a scenario where I buy a C-182 and want to place it on floats. I buy some TSO floats (e.g. whipline, edo etc), but however the "approval" to install those floats on the airplane is a? Would it be an STC or Form 337 or could it be either?

This sounds like a major mod, but I will have to see the design data to really able to come to a conclusion. If its a major mod, it has to be done via an STC.

Where would I find the documentation you are referring to that a "major modification" should be installed via STC?


text:
Does form 337 need to be sent to the FAA prior or after the work has been performed?
Is the Form 337 sent to the FAA prior to the work being performed? Meaning the mechanic awaits the FAAs reply and approval before actually beginning work on the aircraft? Or is the work performed, then documented, and sent to the FAA?

The regulations state that any work must be performed in accordance with either approved, acceptable or specified data on a type certified aircraft. An FAA 337 form is used to report Major Repairs or Alterations to either the Airframe, Engine, Propeller or Appliance. So to answer your question, no, you don't have to send in the 337 form before performing the work because it's purpose is to report the work that was already performed. The form has a conformity statement that must be signed, it states:

"I certify that the repair and/or alteration made to the unit(s) identified in item 5 above and described on the reverse or attachments hereto
  have been made in accordance with the requirements of Part 43 of the U.S. Federal Aviation Regulations and that the information
  furnished herein is true and correct to the best of my knowledge."

You can view the 337 form here:
https://www.faa.gov/documentLibrary/media/Form/Form_337.pdf


text:
What is the effect of the Load Factor on wing Structures?
I am quite confused with the definition of Load factor and how it applies to the wing structures of an aircraft.
For example, you have an Aircraft being subjected to a Load Factor of 2 and whose total mass is 5000kg and wings + fuel mass is 1500kg, and are asked to calculate the Inertia Loading of Said wings.
Would you multiply the weight of the wings by 2? Or does Load factor only affect the lift and not the weight?

If it affects the weight it should affect the lift as well, right? For the flight condition to remain stationary. It sounds like you are almost at the answer.

Related: https://aviation.stackexchange.com/questions/46287/what-is-the-definition-of-load-factor-how-do-you-apply-it

https://en.m.wikipedia.org/wiki/Load_factor
As a start for an aircraft the load factor is the ratio of total lift to total Weight
An easy way to imagine this concept is to understand the idea that when the aircraft is flying at high speed during cruise with a small angle of attack the load factor is very close to 1, this corresponds to the first case on the left of the picture here below
Now what is lift, the picture here below is self explanatory, so it is important to understand that the lift is not always an upward vertical force; when the aircraft is under a coordinated bank angle the lift has two components ; horizontal and vertical.

Now to simplify we shall consider the lift to be totally produced by the wings, while in real flight it is the result of the wing, the body, and the tail.
Since the Aircraft is subjected to a load factor of 2 this means the aircraft as a complete body is subjected to a total lift( not vertical) equal to twice the total weight of the Aircraft
The lift produced is therefore: $2\cdot(5000 + 1500)\,\mathrm{kg}\cdot g = 13000\,\mathrm{kg}\cdot g = 128\,\mathrm{kN}$
If we consider we are in the steep banked turn indicated on the right of the picture above:
The weight of the aircraft body without the wings is a downward force on the root of the wings
Also the wings have their own distributed weights, that produces a torque to the root of the wings
Also the distributed fuel in the wings produces a torque to the wings roots
Also each wing is subject to a distributed lift of $\ 6500\,\mathrm{kg}\cdot g = 63.8\,\mathrm{kN}$
The exact computation are difficult because

we don’t know the bare weight of the wing nor the centre of gravity of the wing
we don’t know the distribution of the fuel in the wing, so we don’t know the centre of gravity of the fuel of each wing.

Therefore it is impossible to calculation the shear forces and the torques at the wings roots.
Nevertheless I imagine the main question concerns the relationship between lift and load factor, And here the most important point is to understand that the lift is not always a vertical force

It appears that this answer doesn't actually answer the main question being asked which was "For example, you have an Aircraft being subjected to a Load Factor of 2...  and are asked to calculate the Inertial Loading of Said wings.  Would you multiply the weight of the wings by 2?"

+1 for making the effort to use Newtons

@quiet flier, what applies to the body applies to the wings. Indeed the weight is vertically down, but the lift is not vertical, it is 60° apart, so yes any weight is neutralized by an oblique force of double magnitude.

The load factor is not the lift force. It is the total force vector in the aircraft + Z-axis (pointing downwards), in units [force from earth gravity]. A picture earlier used in this answer:

In a horizontal steady turn of 60°, the resultant vector of gravity and centrifugal force has magnitude 2 * normal gravity force. So due to some physical circumstance, all elements of the aeroplane experience a force twice that of gravity. The wing and the fuel as well.
In order to maintain the steady turn, lift must also be twice that of normal steady flight. So the inertial loading is twice that of gravity, and lift loading is twice that of steady flight.

For example, you have an Aircraft being subjected to a Load Factor of
  2 and whose total mass is 5000kg and wings + fuel mass is 1500kg, and
  are asked to calculate the Inertia Loading of Said wings.
Would you multiply the weight of the wings by 2?

Yes.
Note that, strictly speaking, kg are not a measure of weight.  You would need to multiply the weight of the wings by two.
In more detail:
In the most general terms, "load factor" could be said to be equal total aerodynamic force divided by weight.  The usual convention is to use "load factor" to mean lift force divided by weight.  The difference between the two results could be very significant in a steep steady-state climb, or in a sideslip.
For the remainder of this answer, "load factor" will be used to mean lift force divided by weight.
As other answers have noted, just knowing the "load factor" is not enough to predict the stresses and strains at the wing root etc-- the load distribution matters as well.
It may help to note the following:

"Centrifugal force" is not a real force, in the sense that it is often applied to an analysis of the flight of a turning aircraft.
Gravitational force (weight) acts with an equal force per unit mass on every single particle of the aircraft, and thus exerts no stresses or strains on the aircraft structure.

However, it is not uncommon to hear the "inertial loading" acting on the aircraft as a whole being described as the combined vector sum of "centrifugal force" and gravitational force.  Whether this is truly "accurate" or "inaccurate" may to some extent be a matter of opinion or reference frame; at any rate the net result is always exactly equal in magnitude (but opposite in direction) to the net aerodynamic force being generated by the aircraft.  In the more narrow case where all aerodynamic forces other than lift add up to zero, the sum of "centrifugal force" and gravitational force will be equal in magnitude and opposite in direction to the lift vector.  In other words, in the case where the net aerodynamic force is equal to the lift vector, the "inertial loading" acting on the aircraft as a whole is exactly equal in magnitude to the lift vector, which is exactly equal in magnitude to the "load factor" times the aircraft weight.
(Note that this conception of "inertial loading" is a little limited-- it considers effects related to turning but not effects related to rotation-- the difference will rarely be significant, except in unusual cases like a flat spin with a high rotation rate-- these nuances only apply to a discussion of the inertial load acting on a given element of the aircraft, not on the aircraft as a whole.)
It would seem that the original question is using the phrase "inertial loading of the wings" to describe the portion of the wing's lift force that is absorbed by accelerating the mass of each wing, and therefore does not contribute to the upward bending moment acting at the wing root.  This would be equal to the weight of each wing, times the "load factor", with the "load factor" being defined as total lift force divided by total weight.
Since we don't know that the center of lift of each wing is the same as the center of mass of each wing, it's only a rough approximation to say that the lift "absorbed" by the "inertial loading" of each wing, calculated as we've stated above, makes no contribution to the bending moment at the wing roots.

An alternate definition of "inertial loading" could construe it to only encompass the ADDITIONAL apparent weight caused by maneuvering.  This would seem to be an inferior definition and also would seem to be not the usual one, but ultimately it just comes down to a matter of convention.

Related-- sort of-- https://www.physicsforums.com/threads/what-is-an-inertia-load.771167/

As a start for an aircraft the load factor is the ratio of total lift to total weight
Since the Aircraft is subjected to a load factor of 2 this means the aircraft as a complete body is subjected to a total lift equal to twice the total  weight of the Aircraft
The lift produced is therefore 2x(5000 + 1500)= 13000kg
The downward force that opposes the lift is the total weight of the aircraft that is 6500kg
The net upward force on the wings is 13000-6500=6500kg
To appreciate intuitively what is load factor, please note that when the load factor is equal to « 1 » the aircraft is not subject to any vertical acceleration, it’s vario is constant
An easy way to imagine this concept is to understand the idea that when the aircraft is standing in the runway or parked, it's load factor value is 1.
Note: For completeness please note the answer is dealing with forces therefore all above Kg units refer to kilogram-force, otherwise you may multiply all the results by « g » to obtain Newton’s.
On the other hand the notion of load factor applies too to satellites therefore « g » should be theoretically considered as a variable function of altitude.

The unit of force is N, not kg!

Yes indeed, I meant kilogram-force, and I preferred to use kilogram-force rather than multiplying every thing by g because of the definition of the simplified definition of load factor which refers to the aircraft weight (even though the weight in this definition represents the vertical force produced by the weight), I will add a note for completeness

No please, there is no such thing as kilogram-force! If you want to be lazy, at least use the word "equivalent" when mixing forces with masses. (E.g. "The net upward force on the wings is equivalent to 6500 kg.")

The same the engine thrust may be expressed in lb, meaning lbf  you may use kg to mean kgf, , please refer to: https://en.m.wikipedia.org/wiki/Kilogram-force

Did you read the part where it says "Kilogram-force is a non-standard unit and is classified in SI Metric System as a unit that is unacceptable for use with SI.[4]"?

The adequacy between lb and lbf is similar to that between kg and kgf, may be too difficult to understand. As far I am concerned I am stopping this pedantic and Byzantine quarrel

Your force units are still wrong though.

@bogl, if you are able to use for simplicity lb instead of lbf, it won’t be so difficult to understand the use of kg instead of kgf.  In spite  of my « laziness » as you say I did the effort to write

@quiet flyer, when the load factor is equal to 1 there is no acceleration, that is the vertical acceleration is zero, thus the vertical speed is contant, thus the vario is constant

True.  In my mind I was replacing "constant" with "quiet" or "silent".  Your statement is correct.

@quiet flyer, continued.. A load factor of about 1 occurs in steady climb, as well in leveled flight, in both cases there’s no vertical acceleration

Not quite sure why all the downvotes on your answer

I believe it is a return to the discussions about lb and lbf, kg and kgf, a contradicted person may call on his friends....

Actually, It appears that this answer doesn't explicitly answer the main question being asked which was "For example, you have an Aircraft being subjected to a Load Factor of 2...  and are asked to calculate the Inertial Loading of Said wings.  Would you multiply the weight of the wings by 2?"

Using units carefully is no luxury or pedantry. People come here to learn from the answers.

About the last sentence of the answer: g depends indeed on longitude, lattitude, and altitude. 9.81 m/s^2 is only a mean value. When people talk about g-loads in satellites, they use this mean value as a pseudo unit. Calculating an actual g for an orbit is a bit pointless.

No for the satellites the actual g  is used the determine the exact orbital level, also some satellites having pressurized nitrogen exits this gaz for repositioning purpose, the correction takes into account the actual g

How do you use the actual g to determine the orbital level?


text:
Where is the modification of an aircraft from floats to wheels and vice versa logged?
How does a maintenance professional, or pilot if allowed, log the change when the airplane is switched back and forth between land and sea? Do they cite the change in the maintenance logbook as performed via STC #, or performed via maintenance manual section XYZ?

If the aircraft was type certified in either configuration, then no STC is necessary. Technically there should be an entry in the logbook for a landing gear configuration change, because it's considered maintenance and all maintenance is supposed to be recorded. Unless the aircraft is registered as "experimental" then the pilot is not allowed to perform anything more than Elementary Maintenance as defined by the regulations.
In Canada you don't need to reference the section of the AMM you performed the work to, they just make it mandatory to make reference to any work performed in accordance with another standard, such as an STC or a component maintenance manual. I've worked in four other countries and they had the same rule regarding the entry of maintenance, but I couldn't say for sure if it was the same way everywhere.


text:
Are canards useful for ultra low flying aircraft?
In this question about canards, they are described as being useful mostly/only for supersonic configurations which are unstable at regular? speeds.
But for a low power, ground hugging aircraft, would a canard help create lift with less width?
This question is part of a human powered dream I have.

This highly depends on the overall conceptual design of the aircraft and there is no ideal configuration for any flight mission profile, except if you have very specific design constraints that will favor one configuration over another. In general, the trend when designing a wing of high aerodynamic efficiency, one that you would need for feasible human powered flight, is to have a traditional configuration of wing and empennage. This is for the wing to operate in clean air and not in the wake of the canard plane. Usually you focus on optimizing the wing and thus you want it to operate in its maximum efficiency.
A design example is the MIT Daedalus Human Powered Vehicle (HPV)

For further technical details regarding human powered vehicles and the their feasibility study you can start with this and discover further on your own.

@PatrickZissou Sorry for the link, I fixed it. If you have a wingspan restriction that is because of aircraft width you could consider a biplane configuration.

woking my way through that pdf, but from your answer im to assume that the more wing surfaces i have the less aerodynamically efficient that design is? does that have to do with wingtip vortices?

@PatrickZissou "the more wing surfaces i have the less aerodynamically efficient that design is" no, the exact opposite can happen. What matters is how the aerodynamic surfaces interact, not how many there are. A box-wing biplane (properly closed at wingtips) theoretically attains the maximum aerodynamic efficiency compared to other wing configurations (proved by Prandlt and Kroo).

@qqjkztd At lower speeds the boundary layer is even thicker and the wake effect can of-course deteriorate wing aerodynamics close to the root, I didn't understand your point. Plus, the canard plane will induce a local flowfield that will lower the main wing's effective angle of attack and thus lift coefficient.


text:
Does a GPS OBS selector use magnetic or true courses?
Under GPS navigation, when we are using the OBS to tune courses. Are these courses magnetic or true?

Magnetic, except for places on Earth where it would be truly ridiculous (such as high latitudes).
Basically, you want to navigate with one reference or the other, no matter which method you are using, to avoid confusion. Using magnetic reference is somewhat of a legacy: it's natural to use it when your primary method of navigation is a compass. Or even not a primary: stars and INS are referenced to True, but the pilot should be able to fall back on the compass at any moment (and cross check the instruments), so a correction (= variation) is always maintained.
GPS naturally works in True coordinates. But to provide 'backward compatibility' it also calculates Magnetic track. To do that, the avionics must maintain a current database of magnetic variation across the globe.
Furthermore, remember that GPS cannot really measure the heading, it can only measure the track. Heading is still measured using gyros, which are periodically corrected using magnetometer, i.e. the same compass.
Modern avionics can be switched between Magnetic and True references (see, for example, the G1000 guide). So technically the answer to your question would be 'it depends on the mode', but usually it is expected to be Magnetic.


text:
What accuracy is required in todays ADS-B position reporting?
I would like to know what accuracy is required for ADS-B position reporting.
For example, mobile phones A-GPS capable have 10 meter position error with perfect conditions.
Is this similar with ADS-B GPS receivers?

This related question links to the relevant FAA regulations.

You can report any accuracy you want over ADS-B, as long as the position source is compliant with TSO-C129 (or later revision), TSO-C145a/C146a (or later revision), or TSO-C196 (or later revision).
ADS-B gives amongst others:

a position,
an associated Navigation Integrity Category (NIC) based on the GPS Horizontal Protection Limit; and
an associated Navigation Accuracy Category for position (NACp) based on the Estimated Position Uncertainty / Horizontal Figure of Merit.

If the positioning system cannot provide integrity or accuracy, the ADS-B transmitter will encode the NIC/NAC as 0 (unknown). This warns users of the ADS-B data that the position source is not to be trusted.
In day-to-day operation, ADS-B is required to provide:

an integrity limit less than 0.2 nautical miles;
a reported accuracy of less than 0.05 nautical miles;

Practically, GPS will occasionally give lower accuracies / integrity, but it will be reflected in the NACp / NIC so that users of the data can decide how to handle this lower quality data for their purposes.
Mobile phone A-GPS chips are typically not certified under the TSO's mentioned above and they don't provide integrity information. These chips are thus not suitable for ADS-B.


text:
How to calculate ground speed using a map with a known scale and time?
If an aircraft flies from point A to B for a distance of 8cm on a chart of 1:1,000,000 in 18 minutes, What’s the ground speed?
It’s a multiple choice question and the possible answers are in ratios.
(#45 in the image)

A. $1:1,105,550$
B. $1:1,250,000$
C. $1:1,740,740$
D. $1:1,074,740$

I can’t change the question but I can explain how it is related to aviation.  The question is from flight dispatcher module Air Navigation, where by in dispatching the aircraft we must know about places where aerodromes are located passing etc and so we learn about maps and charts.. am not off topic the question is 100% aviation related

It's possible that the test creator made a mistake--it happens!  It could be that they accidentally mixed up the answers to two questions while editing the test.  I think you should ask your instructor or aide about the possibility that there's a mistake.

Angie, I appreciate what you are doing, trying to figure out which answer is correct.  I firmly believe that none of the answers can be.  The reason is that the correct answer is a speed, which will be expressed in distance-per-time: kilometers-per-hour, miles-per-hour, nautical-miles-per-hour (or Knots for short).  But the answers you are supposed to chose from are dimensionless ratios.  Speed isn't expressed as a ratio.  It just isn't.  That's why I and others are certain that there is a mistake on the test.

Please let us know what the answer/explanation is.  I'm very curious to know.

What I really want to know is did you and/or any of your classmates figure out that the test was broken before asking the internet?

I'm tend to disagree with your last edit. you can replace "flown by an aircraft" by "traveled by a train" in the question without changing it. Yet, your question was not closed because it was off topic but because it was unclear, and your last edit clarifies it.

If a plane traveled $8\ \mathsf{cm}$ on a map with a scale of $1:1\ \mathsf{million}$, then it traveled $8\ \mathsf{million\ cm}$ in the real-world.
$$8\ \mathsf{million\ cm} = 80,000\ \mathsf{meters} = 80\ \mathsf{km}$$
Convert 80 km in 18 minutes to a speed of kilometers per hour:
$$\frac{80\ \mathsf{km}}{18\ \mathsf{min}} \cdot \frac{60\ \mathsf{min}}{1\ \mathsf{hour}} = 266.6 \frac{\mathsf{km}}{\mathsf{hr}}$$
Groundspeed is traditionally expressed in knots:
$$266.6\ \mathsf{kph} \cdot \frac{0.54\ \mathsf{kts}}{1\ \mathsf{kph}} = 144\ \mathsf{kts}$$
To put this in perspective, 144 kts is a bit fast for a Cessna 172, unless it has a good tailwind, but not at all unreasonable for many small high-performance planes.

The answers to question #44 don't make sense.
The question is "The scale of the chart is...", but the possible answers are all KTS (knots).
The answers to #44 and #45 are clearly reversed.
However, the right answer of 144 kts, is not listed in the possible answers.
In general, I think that test is extremely poor quality.
Question #43 (movement of the earth around the sun) may not even be related to aviation.

Thank you, can you help me to convert the answer to ratio as per scale please

@Angie No, that doesn't make sense. The answer is 144 knots. None of the answer choices you listed make sense as an answer to this question.

for #43, Revolution is a perfectly fine answer.


text:
Re old (1993) US VFR sectional charts-- when did the term "Class E" first appear?
When did the phrase "Class E" or "Class E airspace" first appear on the legend of US VFR sectional charts, to identify the meaning of the thin dashed magenta line?  I'd like to narrow down the date as precisely as possible. Currently I'm aware that this phrase DID appear on the legend of a sectional chart (Hawaiian Islands) effective November 11, 1993, and did NOT appear on the legend of a sectional chart effective August 19 1993.  Please post the "effective date" of any US VFR sectional chart that you are aware of before November 11 1993 in which the phrase "Class E" or "Class E airspace" does appear on the legend, or the "effective date" of any US VFR sectional chart that you aware of after August 19 1993 in which the phrase "Class E" or "Class E airspace" does not appear on the legend.
Basically this question is just asking when the current "alphabet" system of airspace classification first appeared on US VFR sectional charts-- presumably the terms "Class A", "Class B", "Class C", "Class D", and "Class E" were all introduced at the same time.
When answering this question please disregard any reference to foreign (e.g. Canadian) airspace on the legend of the US VFR sectional chart-- the transition to the "alphabet" system of airspace classification may not have been simultanous between the US and all bordering countries.

It was in place in the US already when I started flying in April of 1994. But hadn't been for very long at that point.  Long enough tho to make into the text books.

The date will an AIRAC cycle date. Changes to airspace and procedures are only introduced on cycles of 28 days. The current AIRAC cycle started at 11 October 2018, the next will be 08 November 2018. In 1993 this gives the following options after 19 August 1993: 16 September, 14 October, 11 November. So you can now narrow your search to these three dates.

That is very helpful.  Looks like it had to be either the September date or the October date, and seems most likely to have been the September date based on one of the  answers below.

As indicated by CrossRoads it was on September 16, 1993 that the airspace classification structure changed. The decision was made in 1991, as can be seen in the US Library of Congress:  Federal Register: 56 Fed. Reg. 65415 (Dec. 17, 1991).

SUMMARY:
This final rule amends the Federal Aviation Regulations (FAR)
  to adopt certain recommendations of the National Airspace Review (NAR)
  concerning changes to regulations and procedures in regard to airspace
  classifications. These changes are intended to: (1) Simplify airspace
  designations; (2) achieve international commonality of airspace
  designations; (3) increase standardization of equipment requirements
  for operations in various classifications of airspace; (4) describe
  appropriate pilot certificate requirements, visual flight rules (VFR)
  visibility and distance from cloud rules, and air traffic services
  offered in each class of airspace; and (5) satisfy the
  responsibilities of the United States as a member of the International
  Civil Aviation Organization (ICAO). The final rule also amends the
  requirement for minimum distance from clouds in certain airspace areas
  and the requirements for communications with air traffic control (ATC)
  in certain airspace areas; eliminates airport radar service areas
  (ARSAs), control zones, and terminal control areas (TCAs) as airspace
  classifications; and eliminates the term "airport traffic area." The
  FAA believes simplified airspace classifications will reduce existing
  airspace complexity and thereby enhance safety.
EFFECTIVE DATE:
These regulations
  become effective September 16, 1993,
  except that ...

According to this AOPA article, the change was made in Sept, 1993

In a move to simplify airspace classification, the FAA will rename the different airspace categories on Sept. 16, 1993. In order to fall in line with ICAO (International Civil Aviation Organization) practices, it will replace descriptive titles, such as Terminal Control Area, with alphabetical designators, such as Class B Airspace. This change will be phased in gradually. Charts and references will carry both designations until pilots get used to the transition.

https://www.aopa.org/members/ftmag/article.cfm?article=1054
And some more background

A Brief History of Aeronautical Charting
To understand the change that GIS has brought to the National Geospatial-Intelligence Agency (NGA), it is helpful to be familiar with the history of aeronautical charting.
Shortly after the Wright brothers made their historic first flights, the skies began to fill with aircraft. Visibility was the key navigational tool at that time. Aircraft were limited to short flights in clear weather and used transportation routes to navigate by, flying low to the railroads during reduced visibility. Early pilots began making personal notes to help them navigate to and land at increasingly distant airports, and enterprising pilots sold these notes to other pilots, but air travel remained limited by visibility.
In the 1930s, radio technology made it possible for pilots to navigate farther distances through unfamiliar surroundings in reduced visibility. In 1941, the first instrument approach and landing charts were developed, serving pilots with the need to land in low visibility.
By this time, aviation was a matter of interest worldwide. Many organizations began drafting standards for aviation-related maps, charts, and information. During World War II, the demand for charts increased dramatically. By 1943, production had increased from around 500,000 per year to more than 11 million. The U.S. Army and Navy air forces each built their own custom charts to fit their wartime needs.
By the end of the war, it was clear that standardized products and symbology were needed to support international air travel. The following years saw the establishment and maturity of many of the aeronautical- and aviation-related agencies and associations that we see today, such as the U.S. Federal Aviation Administration and the United Nations International Civil Aviation Organization (ICAO), each mandated to ensure the safe, efficient, and orderly evolution of international civil aviation.
Today, these organizations and others drive the look and feel of aviation products worldwide. They have also mandated an update cycle to ensure that all aircraft are flying on the same data. Depending on the region of the world, this cycle is effective every 28 days or multiples of 28 days. It is easy to see how a map of the world's airports and airways, updated every 28 days and limited by international standards, can become a huge challenge. This challenge is the mission of NGA's Aeronautical Division.

http://www.esri.com/news/arcnews/summer07articles/a-brief-history.html

PS I would really interested to know if anyone comes across a sectional chart on which the dashed magenta line is identified BOTH as "Class E" or "Class E airspace", AND as "Control Zone at airport without control tower and Control Zone extension without communications requirement" or something to that effect,  It appears that this would have only happened-- if ever-- sometime after August 19 1993 and before November 11 1993.  But, that's really a new question isn't it.

Well that is very interesting.  Can give you give a specific airport or region where this was considered to be the case?  Also it seems you might want to post your comment as answer to this related question -- https://aviation.stackexchange.com/questions/48106/does-an-svfr-clearance-extend-to-echo-surface-extensions -- I see you were active in that discussion in comments but didn't post an answer.  Even if it is superceded by later information it is an interesting data point.  Anyway thanks for the note.

Btw re "airport traffic areas" -- here is something I noticed while looking through old sectional charts etc -- "Also by that time (1974), an "Airport Traffic" area was a different thing from a "Control Zone", requiring radio communication with the tower for entry, with a smaller, standardized diameter and a much smaller, standardized vertical height."

(ctd) "Airport Traffic Areas" were not even depicted on sectional charts, because they were automatically present at all towered airports, and they were standardized in diameter and height. Even though Airport Traffic Areas weren't depicted on sectional charts, they were referenced on the chart legend through at least mid 1983 in the language concerning towered airports, but by sometime in late 1988 that reference had been dropped."  -- (  this comment is NOT intended to suggest that the concept of Airport Traffic Areas no longer existed after late 1988. )

(Context for above 2 comments-- https://aviation.stackexchange.com/questions/35297/which-parts-of-class-e-airspace-can-an-ultralight-part-103-fly-in-without-prio/55714#55714 )

And we still have some TRSAs around too, similar functionality as Class C/D, but bigger geographic area. KELM and KBGM come to mind, as I fly out that way on occasion, middle of NY above PA border.

Thank you for that note 757toga-- one of these days I will post another question -- "when did control zones FIRST appear on US aeronautical charts" -- but not right now!

Might as well ask when US aeronautical charts first came out. I wonder if any states still put out their own charts.

I would actually be interested to know that (the first part), someone should ask


text:
Is there a niche market for A&P mechanics with an aerospace engineering degree?
I've noticed a few people posting on this site who I would guess are aerospace engineers.
I am an A&P Mechanic, who is currently in the process of applying to college for an aerospace engineering degree.
My question is this:
Does a niche exist that would involve both skill sets, and will the A&P license/experience give me a competitive edge for hiring in some companies?

There is certainly a niche for both skill sets. Part of aerospace engineering is considering maintenance. There are multiple types of positions where having an A&P license would be a bonus.

During the design of an aircraft, maintenance must be taken into account. Projected maintenance costs are important to the success of a design. Engineers must address this during the design of new parts.
Manufacturing will have a lot of aspects in common with maintenance. Engineers must support manufacturing requirements in the design phase. Supporting emerging issues in manufacturing is also an important role.
Engineering is also needed to support regular maintenance tasks. Problems come up that aren't covered in the manual, and engineers will need to advise on a solution.

Based on these subjects, the following are a few types of companies will have some positions where an A&P license could help:

Designers of aerospace parts
Manufacturers of aerospace parts
Airline maintenance departments
Maintenance, Repair, and Overhaul (MRO) companies

This focuses mostly on the commercial side of things. You can also find either civilian or military jobs supporting the military equivalent of these functions as well.


text:
What are the effects of angle of attack on turbines in composed delta wings with jets in upper side?
: a layperson doubt. What would happen during take-off and landing of a machine as Boeing X-48, because of the high angle of attack, the steep attitude of the airplane: would this difficult air supply to turbines?

Very little air is supplied to the turbine for cooling and has quite a stable pressures because of the circuit and regulators. Turbine main flow is hot combustion gas from combustion chamber. So direct answer to your answer is "unaffected"

I suspect this question is more directed at the overall performance of such a jet engine installation during high AOA. Compressor stall in this regime would certainly be a design consideration.


text:
What will the 737 MAX 7, 8, and 9 ICAO IDs be?
Since the ICAO identifiers B737, B738, and B739 are already taken, what will the ICAO identifier for the 737 MAX 7, 8, and 9 be? Would it possibly be B73M7 etc?

This seems to be entirely speculative.

This question appears to be off-topic because it is about speculating on future events, we don't have a crystal ball

@jwenting Since a designator has already been assigned to the 737 MAX series, there is no speculation at all, just reporting of a fact. No need to close it IMHO.

The new Boeing 737 MAX is based on the Boeing 737 Next Generation family, which it will replace. Also note that 737 MAX is still under development and is scheduled to release in 2017.
Update:
(Source)
The first 7 is omitted and the suffix is now an M for Max, e.g. B37M for the Boeing 737 MAX 7.
Wikipedia has complete list of ICAO codes here.

ICAO Aircraft Type Designators: Search for Boeing and you will find 737 MAX in the list.

That somewhat surprises me, as I'm sure some 737NG's will be in service for some time after the MAX comes out. Oh well!

@nathreed they're effectively 738 and 739 aircraft with upgraded interior and engines. For ATC purposes they're no different, so no need to distinguish them.

Initially they will go with the same designators as the B737NG series. If the performance is very different from the NG, new designators may be chosen. I don't think this will be necessary.

Note that an ICAO aircraft type designator is always 4 characters; B73M7 is too long.


text:
Why would Boeing be under review if crew-error is determined to be the cause?
The captain on Lion air's flight 610, re-trimmed the aircraft through 21 MCAS activations. The first officer, who was given control of the aircraft, got 5 more. Although it is speculated that neither pilot executed the required stabilizer trim procedure, the report does not specifically state whether or not that procedure was actually run. Source
The captain on Ethiopia Airlines flight 302, tried engaging the auto-pilot, on the faulty side as well, and despite that being the first step for the procedure, to disengage, he tried multiple times to do otherwise, then skipped over the second step, which was to disengage auto throttles, this allowed their airspeed to build up around 390. I’m sure this didn’t help the nose down force, but ultimately, they re-engaged the system which allowed MCAS to drive the nose down further. Boeing's CEO stated these failures to follow procedures is what led to the crash. Source
The question, then, is this: if the crashes each resulted from pilot error, why is Boeing under so much scrutiny?

This is largely opinion based (which is out of scope here) but news outlet are covering both sides of the story depending on where you look. Boeing a very large American company and their stock is a major market player. Many of the financial news outlets are covering the company because its having a tangible impact on the economy.

@Dave How can it be opinion based, when I got this from the reports, and not something I convinced myself?

mostly because of the line I have no problem with Boeing being faulted, why is everyone totally ignoring another issue people are not ignoring the issue, some are discussing it and why news outlets chose to report on and cover certain things is surely an opinion

If others dont think its an opinion issue it wont be closed.

@Dave I’m not trying to bring my opinion in here, but I had to mention it, because I don’t wanna imply that Boeing is totally innocent, I’m just trying to make it clear that I do understand the fault on both sides. But the reporting is one sided and definitely far fetched.

This is both opinion based (why is a company receiving media attention) and borderline speculative (where it involves the two 737MAX crashes, which are the subject of ongoing investigations), so I foresee its closure in the near future. Or, as is customary in other parts of the net: inb4lock

I've edited the question to remove the "opinion" feel, but still hopefully stick to the intent of what you're asking.  If I missed that intent, please feel free to re-edit.

Nicely done @Jimmy. I also like the answer of Robin, which proves that the question can be addressed without too much opinion. I now vote to reopen.

@DeltaLima In my opinion this is till too much focused on the recent accidents, which are still under investigation. I vote to leave closed.

In aviation (and other safety critical areas) it's not enough to just look at the first cause of an accident, you have to look at why that mistake was made, and why that thing happened, as far back up the chain as you can. Then you try to address all the problems.
So, when a pilot makes a mistake, it's tempting to say "the pilots was an idiot. Case closed." However, then you've got to wonder why the company employed idiots, and how many  others are flying. That implies that there's something wrong with the pilot licencing and testing rules, and that has huge implications.
If we assume that these pilots weren't idiots, we have to ask why they made a mistake, because other good pilots could make the same mistake. Anyone who has played a computer game knows that mistakes are inevitable when you're under enough stress, just like a well built bridge will still break if it's overloaded.
You could conclude that they hadn't been trained well enough, which raises the question "Why?". Apparently the pilots did all the required training, so maybe the training was at fault. But it's not enough to just improve that piece of training, you've got to ask why again. Was it not checked? What else hasn't been checked properly? How do we know that any future training will be properly checked? Also, what incentive did the person writing the training have to miss things out, and does it apply elsewhere?
If you don't find and fix the root of a problem, it will continue to grow until it pops out somewhere else and causes another tragedy.

I like your Reply a lot, thanks for that! We must find out why they didn’t prioritize the emergency, and didn’t follow through with procedures. Unfortunately Boeing and airbus can make great aircraft all they want, but malfunctions will still occur. And we just have to learn how to deal with them. Unfortunately “learning” in aviation is almost always through someone dying. It’s just a complex industry that people sometimes expect way too much

"Unfortunately Boeing and airbus can make great aircraft all they want, but malfunctions will still occur. And we just have to learn how to deal with them." This aircraft, and MCAS in particular, and the development process used to create MCAS, is clearly not "great".   Believing that malfunctions will occur, and we just need to learn to deal with them actually has a formal term:  "normalization of deviance".   Aviation is (and should be) built to the highest standards, accepting malfunctions as "normal" is not appropriate.

If the question gets closed, I hope you write another one to attach this nice answer to.

@abelenky I’m not making any malfunction seem okay, I’m just saying that the malfunction has already existed, for decades now. And the training to stop such has been there. So we need to find out why these pilots were not properly trained. Obviously there has got to be some repetitive training and also learning to not freelance.

@Firefighter1 This isn't just about a malfunction. Boeing found that the new airframe's behaviour did not meet the established safety norm (requirement?) that a commercial aircraft should be inherently stable, so they created the MCAS to compensate; which they believed would make the new airframe's behaviour as safe and intuitive as the old (proven) airframe. They believed it safe and intuitive enough that pilots were not informed during their training, and here we are with 2 fatal accidents. What other assumptions have they made that we are not aware of, and what more accidents await?

(continued) What other assumptions have they made that we are not aware of, and what more accidents await? This is a real doubt in many travellers' minds, and if Boeing's business/viability suffers because airlines have to shelf their 737 MAX aircraft or cancel existing orders, it would have a measurable impact on the US economy and perhaps those of Boeing's suppliers, as @Dave pointed out. It is certainly not a small matter.

@Firefighter1 I’m just saying that the malfunction has already existed, for decades now. I think this is where the misconception is. The MCAS is a new subsystem created for the 737 MAX series, to counteract a significant modification to the original 737 airframe. The modification should have invited scrutiny from the FAA, but did not, which is why the FAA's role/responsibilities/diligence have also been questioned.

737-MAX and MCAS were introduced in 2017 (production started in 2014).  That is in no way "decades".   No training was provided because (in theory) it worked the same.   The checklists you are referring to are for runaway trim, which is the trim running continually.   What actually happened was intermittent incorrect trim adjustment, and there currently is no checklist or training for that.


text:
Are these IFR Pattern colors following a standard?
I recently came across a series of IFR practice patterns such as the example below that use red for descent and blue for climbs.
Are these colors standard in the IFR world or was it just made up for that document?

Published IFR procedures are always black and white only. But that doesn't stop a person making training material to use colours to good effect, and that seems like a particularly well designed example of a custom training aid.

They don't, but maybe they should. Although, as most are printable from home those without color printers wouldn't get the benefit.

"Always" is a strong word.

@GdD You don't want colours in a dark cockpit. High contrast B&W is it. The place you will see colours is low alt IFR charts where the terrain areas are depicted in light green, but has no practical use. In a dark cockpit you won't be able to make out the green.

NOAA (and probably other government sources) may publish "always" in B&W only, but Jeppesen does use a few shades of brown to depict terrain on their approach charts, and will sometimes use a red-ish color to title certain notes on departure and arrival charts (typically, airspeed restrictions).  In any event, though, what's depicted in the OP looks like somebody's convention for their training aid, and is definitely not anything in widespread use.

@JohnK that is incorrect, as randomhead indicated. USG charts include several shades of brown to indicate terrain or airport hot spots.

Yeah, that was a couple of iterations ago -- we referred to them as "NOS" charts, but that term isn't current either.  So it's just "the FAA" now.  Either way, the underlying point remains, that Jepp does add color to some of their products.

@Timbo Not to the text and track lines, things you must be able to see in a dark or red lit cockpit. The colours vanish or are washed out.

I don't remember any such convention being any sort of widespread standard in aviation generally. Some conventions, like colors in the cockpit (i.e. magenta = target, amber = caution, red = warning) are basically universal; what's shown in the OP is nothing like that.


text:
In Ethiopia, what are the minimum hours to be a pilot in a passenger jet?
With regards to the flight crew on board the Ethiopian flight, I have read many times that the young F/O with only 200 hrs wouldn't have been allowed to transport passengers if he were a pilot in the USA. Like in this article:

In the Ethiopian Airlines crash this week, one of the pilots had just 200 hours of flight time, less than a seventh of the time the F.A.A. generally requires to fly a passenger plane.

I don't know about FAA regulations, but cadets that come out of MPL or Integrated ATPL route have around 250 hrs and hold an ATPL frozen that allows them to be a co-pilot of a jet with hundreds of pax. Even stranger for pilots with an MPL who are not allowed to fly in single pilot planes until 1500 hrs.
Are Ethiopian requirements really so different compared to western countries (North America, Europe, Australia, NZ)?

On Mar 18th 2019 the airline clarified, the first officer had accumulated a total of 350 flight hours

from AVHerald

IIRC in the USA until couple of years ago one also only needed CPL with multi-crew and type-rating to fly as F/O. The reason for change was apparently to adjust the job market and not related to safety—two many new pilots wanted to fly so F/Os on regional lines ended up working for peanuts. Yes, the F/O in Ethiopian 302 accident was a complete beginner with just 200 hours, but was appropriately paired with captain who had about 8000 hours.

@JanHudec It was not due to the job market. The regulations were changed due to a number of regional airline accidents, particularly Colgan 3407, where inadequate pilot skills were identified as a major cause. A significant change in the industry was that the smallest regional aircraft are now much larger, the 19 seater first plane became, 30, 50, and is now effectively a 70-seater.

@user71659 The pilots of Colgan 3407 had more than the 1500 minimum however and wasn't a factor in that crash.  The main issue with Colgan 3407 was the violation of the sterile cockpit rule (the captain and FO were chatting and not flying the plane).

Are you asking what the Ethiopian requirements are to fly as a first officer? Or are you asking if the "less than a seventh" comment is correct, i.e. what are the American requirements?

I am asking whether Ethiopian requirements are much different compared to developed countries (North America, Europe, Australia, NZ)

@DLH That was not the main issue. The main cause was failure to recover from a stall. Regardless, it was clear pilot incompetency, and it led to tightening of standards. The ATP requirement was clearly linked to the accident.

@DLH - The primary issue for the Colgan 3407 crash was pilot fatigue and crew rest period. While the crew did chit chat (they where talking about their pilot fatigue) and became distracted, once the stall occurred it was lack of skill and pilot error on the part of the FO and pilot fatigue of the pilot that ultimately killed all on board.

For Commercial Pilots: 250 hours; For ATP: 1500 hours.
Source: ecaa.gov.et (PDF; see Sections 3 and 6).
The flight hours requirement does not seem to be different for Pilot and Co-pilot. (See Section 6.6)


text:
How does the EPR reading behave in reverse, and in reheat modes?

Will an engine pressure ratio indicator (EPR) show the same at full mil thrust as with full reversed thrust?
What does the EPR indicate at afterburner active? Will it just show the same as for max mil thrust?